1. Field of the Invention
The present invention relates to a magnetic card in which a bar code printed in advance is prevented from being counterfeited, and a card reader apparatus using this magnetic card.
2. Description of the Prior Art
In a magnetic card used in a card terminal apparatus such as a card type vending machine, a magnetic track is formed on which value information corresponding to a pre-paid amount is magnetically recorded is formed. When the magnetic card serving as a pre-paid card is used in the card terminal apparatus, the value information recorded on the magnetic track is read out, service corresponding to this value information is permitted. This magnetic card has a bar code recording area independent of the magnetic track to improve its security, and a bar code corresponding to an identification code representing, e.g., the face value or the like of an unused card is printed in this bar code recording area. Therefore, in the card terminal apparatus, the bar code information formed in the bar code recording area is read out each time the magnetic card is used to identify the authenticity of the magnetic card, and it is determined depending on this identification result whether the card can be used.
FIG. 8A shows a conventional magnetic card in a card convey direction to explain the above bar code recording area. A magnetic card 1 is constituted by sequentially forming a substrate 11, a magnetic layer 12, a bar code protection layer 13, and an overcoat 14 from the lower direction. A bar code 15 is printed on the magnetic layer 12 with an infrared absorption ink. When infrared rays are radiated on the overcoat 14 of the magnetic card 1 having the above arrangement, the infrared rays are transmitted through the overcoat 14 and the bar code protection layer 13 and then absorbed in the bar code 15. In addition, infrared rays which are incident on a portion having no bar code 15 formed thereon are reflected by the surface of the magnetic layer 12, the reflected light is transmitted through the bar code protection layer 13 and the overcoat 14, output from the surface of the magnetic card 1, and then detected by a detection unit (not shown) of the card terminal apparatus. As a result, the card terminal apparatus can identify the authenticity of the magnetic card 1 by reading the pattern of the bar code 15 formed on the magnetic card 1. If it is determined on the basis of the identification result that the magnetic card is authentic, a predetermined card process such as a process of reproducing information from the magnetic track or a process of recording value information corresponding to the bar code is performed.
FIG. 8B shows a prior art magnetic card 1 which is constituted such that the surface of the magnetic layer is in contact with the overcoat 14 by decreasing the thickness of the bar code protection layer 13, thereby decreasing the total thickness of the magnetic card 1.
In the conventional magnetic card 1, in order to prevent visual identification of the printed bar code 15, the bar code 15 and the magnetic layer 12 are covered with the bar code protection layer 13 and the overcoat 14. However, if the overcoat 14 and the bar code protection layer 13 are filed by a file or the like, the pattern of the bar code 15 is exposed to be easily, visually recognized. As a result, the pattern of the bar code 15 of the magnetic card 1 can be easily decoded. In the thin magnetic card shown in FIG. 8A, the probability of decoding the pattern becomes higher. In addition, when the bar code 15 can be illegally rewritten by decoding the pattern of the bar code 15, illegal value information based on the illegally rewritten bar code 15 can be recorded on the magnetic tracks. Therefore, the magnetic card 1 can be counterfeited and illegally used.